Propellers of the abovementioned type, for example on boats, are driven by a drive motor. The torque delivered by the drive motor is transmitted to the propeller via a drive shaft leading from the motor, a transmission mechanism and a propeller shaft. Since the propeller is designed with a through-opening in the hub thereof, with splines arranged in the through-opening, and the propeller shaft is designed with corresponding splines, a rotationally fixed connection is obtained, when the two (propeller and propeller shaft) are joined together, so that the torque delivered by the drive motor is transmitted to the propeller.
When the propeller of a boat is caused to rotate with the aid of the drive motor, the propeller generates a compressive force which drives the boat forward or backward depending on the direction of rotation of the propeller. The compressive force gives rise to a reaction force which is transmitted to the propeller shaft via the propeller hub. The propeller shaft is therefore provided with a flange against which the hub bears in order to take up the compressive force when the propeller drives the boat forward, and an end nut against which the hub bears in order to take up the compressive force when the propeller drives the boat backward.
A problem with the abovementioned type of spline connection between the propeller hub and the propeller shaft is, however, that only the torque delivered by the drive motor can be transmitted via the spline connection. Consequently, the resulting compressive force is transmitted completely via the flange or end nut, which means that these have to be given a relatively robust and therefore bulky construction, particularly in the case of high-power motors. Another problem is that the propeller hub has to be made particularly robust, and therefore bulky, at those parts which are intended to bear against the flange or end nut. This is particularly problematic in what are known as twin-screw arrangements, that is to say two propellers rotating counter to one another on the same longitudinal geometric axis, where one propeller is connected to a propeller shaft extending through a bore in the second propeller's propeller shaft, and where a large number of components therefore have to be accommodated within a very limited space.